I. The Field of the Invention
The present invention relates to compositions including minerals complexed by amino acids. More particularly, the present invention relates to compositions including amino acid/mineral compounds having increased solubility, absorption, and/or bioavailability.
II. The Related Technology
Chelated minerals have become well known for nutritional supplementation. A wide range of nutritionally-relevant minerals have been chelated by amino acids in order to improve the therapeutic potential of the mineral. In part, amino acids have been shown to increase solubility of the mineral in the digestive system, thereby increasing bioavailability of the mineral.
The structure, chemistry and bioavailability of amino acid chelates is well documented in the literature, such as in Ashmead et al., Chelated Mineral Nutrition, (1982), Chas. C. Thomas Publishers, Springfield, Ill.; Ashmead et al., Intestinal Absorption of Metal Ions, (1985), Chas. C. Thomas Publishers, Springfield, Ill.; Ashmead et al., Foliar Feeding of Plants with Amino Acid Chelates, (1986), Noyes Publications, Park Ridge, N.J.; and U.S. Pat. Nos. 4,020,158; 4,167,564; 4,216,143; 4,216,144; 4,599,152; 4,725,427; 4,774,089; 4,830,716; 4,863,898; 4,725,427; 5,292,538; 5,516,925; 5,596,016; 6,114,379; 6,166,071; 6,407,138; 6,426,424; 6,458,981; 6,518,240; 6,706,904; 6,710,079; and 6,716,814, which are all incorporated herein by reference.
Iron is an example of a nutritionally-relevant mineral that is utilized in a variety of biological processes. While iron may be present in many foods of an ordinary diet, it may not be adequately absorbed into the body. As a consequence, it is estimated that approximately 500 million people may have iron deficiency even though their food includes iron. Contrary to popular beliefs, iron deficiencies are not limited to developing countries, and are present in a significant portion of the developed world. In the United States, about 11% of women between 16 and 49 years of age and about 9% of children between 1 and 2 years of age have been classified as iron deficient. Iron deficiency, such as iron deficiency anemia, has been treated with oral iron supplementation in the form of iron chelates (e.g., FERROCHEL® from Albion Advanced Nutrition).
Dietary iron can be obtained either as heme iron from beef, lamb, pork, and poultry or as nonheme iron from vegetables, whole grains, fortified grain products, and supplements. Beef and chicken liver are the richest sources of iron. In general, red meats (e.g., beef, veal, lamb) are richer in iron than white meat (e.g., poultry and fish). Heme iron is more bioavailable than nonheme iron because it is a soluble complex absorbed intact by endocytosis. Nonheme iron may form insoluble complexes in the alkaline medium of the small intestines rendering it unavailable for mucosal uptake. Absorption of nonheme iron also depends on availability of an iron-binding mucosal transport protein (e.g., transferrin) to facilitate uptake from the intestines.
Of the two forms of nonheme iron in the diet, the reduced form (e.g., ferrous) is more bioavailable than the oxidized form (e.g., ferric). On average, 10% of dietary iron is available for mucosal uptake, but the efficiency of absorption can increase three-fold in times of need because of increased synthesis of mucosal iron-binding protein. In addition to increased demand, intestinal absorption of nonheme iron is enhanced in acidic pH and in the presence of free amino acids. Acidic foods, such as tomato sauce or orange juice, consumed with a nonheme iron food source, such as pasta or breakfast cereal, can significantly increase the amount of iron absorbed from the meal.
Nonheme iron absorption efficiency may be reduced by use of antacids or high dose calcium supplements. Phytates and oxalates may also decrease bioavailability of nonheme iron. High dose supplements of calcium, zinc, manganese, magnesium, and/or copper can reduce iron absorption through competition for mucosal uptake. Tannic acid in coffee and tea can also adversely affect iron absorption. Consumption of coffee or tea one hour before or after consumption of a nonheme iron dietary source can reduce absorption of this mineral by as much as 40%.
Iron deficiency anemia is the most common nutritional deficiency disease worldwide. Inadequate dietary intake and relatively inefficient absorption of iron from low cost sources contribute to poor iron status. Iron is distributed in small amounts in the food supply with an average of 10 mg provided in each 1000 kcal of food consumed. Groups most at risk of iron deficiency are children, pregnant and menstruating women, and repeat blood donors. Blood loss of significant amounts for any reason can also contribute to iron deficiency.
Impairment in energy metabolism and neurological function may occur with depletion of iron reserves even in the absence of hematologically detectable anemia. Uncorrected iron deficiency (>120 days) can progress to iron-deficiency anemia, which is characterized by low hemoglobin levels from lack of sufficient iron for synthesis, and by decreased mean corpuscular volume of red blood cells due to lack of sufficient iron to support growth. Microcytic hypochromic changes must be accompanied by low serum ferritin to confirm that the hematologic changes observed are specific to iron status and not related to either copper or vitamin B6 status.
Other symptoms of iron deficiency with or without clinically detectable anemia include short attention span, apathy, irritability, hypoactivity, and impaired cognitive development in children. In the adult population, iron deficiency contributes to poor immunocompetence, irregular heart beat, and fatigue. Paleness of oral mucosal tissue, concave pale nail beds, and behavioral changes can also signify the presence of iron deficiency.
Even though amino acid chelates have been found to be beneficial for improving the bioavailability of mineral supplements, additional improvements are continually being sought. In part, this is because the industry is responding to consumer demands for mineral supplements that are more effective, more efficient, and less costly. As a result, mineral supplements such as amino acid chelated minerals, are available in a wide variety of formulations and modalities of administration. However, it has been recognized that additional improvements in the preparation and/or formulation of amino acid chelates can further improve the therapeutic value of mineral supplements.
Therefore, it would be advantageous to have an amino acid and mineral-containing composition and method of preparation that can provide increased mineral solubility and/or bioavailability. Additionally, it would be beneficial to have an amino acid and mineral-containing composition that has been prepared to have increased solubility and/or increased absorption characteristics.